Benefits of UVC in Health Care Facilities

Posted by Jim Shiminski

UVC Emitters are ideal for hospitals, clinics, laboratories, hospices, senior facilities and medical offices.

Steril-Aire UVC Install

Steril-Aire UVC Installation

UV light in the form of germicidal lamps has been used since the late 1800s to kill the types of microorganisms that typically cause indoor air quality (IAQ) problems — bacteria, mold, yeast, and viruses.

Installed at the cooling coil and drain pan in an HVAC system, UVC eliminates surface biofilm — a complex matrix of mold, bacteria, viruses and debris.

Key Benefits to Health Care Facilities:

  • Improved IAQ:  Significantly decreases mold, bacteria and virus introduction to supply air stream.  Reduced Hospital Acquired Infections (HAI) contributing to reduced hospital stays and reduced liability.
  • Energy Savings:   Lowers energy costs by improving HVAC system heat transfer and increasing net cooling capacity.  Offers a return on investment in less than 2 years.
  • Maintenance Savings:   Continuously cleans coils, drain pans plenums and ducts, reducing or eliminating manual cleaning and the use of harmful chemicals.
  • Water Conservation:  Reclaiming clean condensate for tower makeup, irrigation or gray water flushing reduces water and waste water costs.
  • LEED Contribution:  UVC may contribute to LEED points in one or more areas.

From reducing energy consumption and controlling costs, to optimizing human and mechanical productivity, UVC solutions make real sense for Health Care Facilities.

 “Our experiences have shown us repeatedly that UVC enhances indoor air quality and infection control, while saving on maintenance labor, materials and downtime. The substantial energy savings achieved have been a great bonus. Since our administrators now have a high confidence level in the effectiveness of UVC lights, we will continue to equip both new and existing air handling units with the devices.”
— Florida Hospital  –  Orlando, Florida

See related Blog Posts for more information on UVC Emitters:
Ask Rick: What is UVC? 
Ask Rick: UVC Emitters | How will UVC provide cost savings? 
Does Coil Cleaning Save Energy?

For manufacturer information see: Steril-Aire Healthcare Brochure

Steril-Aire Stakeholder Outreach Program

High Pressure Water Atomizing Humidifier | Energy Savings

Posted by Jim Shiminski

It’s all in the numbers.

Look at the cost differences listed below for typical humidification systems.

Humidification Choices Cost Comparison

 

 

 

 

 

 

 

 

There it is.  It’s pretty simple.  Even if these numbers from a leading manufacturer are off by a factor of 10 (or even 100),  it still makes complete sense to evaluate high pressure water humidification as an alternative.  Why wouldn’t you. 

Maybe it needs to be shown differently.

Humidification Choices Cost Comparison Graph

 

 

 

 

 

 

 

 

Looks even more compelling in this view.  

A typical high pressure system consists of a high pressure pump, delivering demineralized water at 1,000 psi to a series of stainless steel nozzles creating a fine, uniform mist.  The droplets created evaporate spontaneously to humidify the air.  The typical control system combines the action of an inverter, which controls the pump flow-rate, and a series of solenoid valves that activate only the nozzles required.  Controls ensure the system always operates at the optimum pressure to atomize the water, over a wide range of flow-rates.

The biggest advantage of high-pressure water atomizing humidifier is operating costs (See Above).   A typical high-pressure system uses one horsepower for every 500 lbs. of water. That’s equal to about three percent of the energy usage of a compressed air system and about one percent of the energy usage of a steam system. Pennies on the dollar.

Like more information on High Pressure Atomizing Humidifiers….See related Blog Posts:
Ask Rick: How does a high pressure atomizing humidifier work?
Ask Rick: What is adiabatic humidification?

Product Literature from Carel:  Carel-Humifog

Project Snapshot | Energy Recovery Wheels For Hospitals

Posted by Jim Shiminski

Walter Reed National Military Medical Center

 

 

 

 

 

 

 

 

 

 

Project Overview
Project Name: Walter Reed National Military Medical Center
Location: Bethesda, Md.
Floor area: 515,000-square-foot ambulatory care building; 162,000-square-foot hospital addition; 450,000-square-foot hospital renovation; and 943-space parking structure
Number of floors: Various
Number of beds: 174 (of 345 total beds)
Design-build cost: $755 million
Groundbreaking date: March 2008
Opening date: July 2011

Project Team
Owner: U.S. Department of Defense
Concept design architect: HOK
Concept design engineer: AECOM (formerly HSMM)
Designer of record: HKS
Associate architect: Wingler & Sharp Architects & Planners
Historic preservation: Hartman-Cox Architects
General contractor: Clark Construction Group and Balfour Beatty Construction joint venture
Interior design and medical equipment planning: HKS Healthcare Interiors and Wingler & Sharp Architects & Planners
Mechanical/plumbing design-build engineer: Southland Industries
Electrical design-build engineer: M.C. Dean Inc.
Structural engineer: Cagley & Associates
Landscaping: Dewberry

Thermotech Wheels in Walter Reed Hospital

Here in New England we have specified energy recovery wheels in many hospital and university lab applications.  Other noteworthy facilities around the country are also embracing the technology.

Thermotech was very proud to be associated with this project at Walter Reed.  The design build team installed an innovative heat recovery system using enthalpy wheels to exchange energy between exhaust and incoming air.  The system is highly efficient and provides 100 percent outside air.   And, because it uses two ducts (supply and exhaust) instead of the standard three (supply, return and exhaust), the system was easier to install in the limited space above the medical center’s ceiling.

 

Thermotech Wheel on Walter Reed HospitalEleven 16-foot diameter enthalpy wheels contribute to the natural ventilation in Walter Reed’s America and Arrowhead buildings. They play a substantial role in decreasing the hospital’s HVAC costs by 28 percent.

 

 

 

Related Blog Posts:
Energy Recovery Wheels | What is an Enthalpy Wheel?
Project Snapshot: Lab Exhaust Energy Recovery Systems | Mass General Hospital CNY149
Ask Rick: Energy Recovery Wheels on Laboratory Fume Hood Exhaust?

Energy Recovery Wheel | Purge Section

Posted by Jim Shiminski

Thermotech Wheel With Purge

There are two ways that air can leak from the exhaust side to the supply side of a wheel:

Cross-Flow Leakage – occurs when air leaks from the exhaust side to the supply side through the seals or any gaps in the construction.

Carryover Leakage – occurs in rotary recovery wheels as the wheel rotates from the exhaust to supply air stream.   A small amount of exhaust air can be carried over in the flutes of the wheel as it passes by the center-line seal.

Cross-contamination can be virtually eliminated by a “Purge Section”, which is an integral part of the casing design.  The purge section utilizes the pressure difference which exists between the outdoor and return air streams to “purge” the transfer media with clean outdoor air prior to its rotation into the supply air stream.  The figure below provides a graphic representation of the purge section operation.Purge Preventing Carryover Leakage

The purge section is adjustable.  This allows for optimizing the required purge volume during system start-up, regardless of the pressure difference between the outdoor and return air streams (provided that the return air pressure is lower than that of the outdoor air).

Be advised,  an energy recovery wheel purge section is a feature that will reduce carryover leakage.   It will not guarantee zero leakage from the exhaust side to the supply side of the unit.   Energy Recovery Wheels | Understanding Cross Contamination / Leakage

Also,  do not use a purge section on every unit.  If you are not concerned with carryover then don’t use a purge (like in a typical school application).  The purge comes with an energy penalty.  Air flows are typically increased from 5 to 7% on both the supply and exhaust side to feed the purge. 

Related Blog Posts:
Energy Recovery Wheels | What is an Enthalpy Wheel?
Ask Rick: Energy Recovery Wheels on Laboratory Fume Hood Exhaust?
Ask Rick: How much cross contamination occurs with an Energy Recovery Wheel?

Diesel Generator Exhaust | Now Classified as a Carcinogenic to Humans

Posted by Jim Shiminski

Emergency Diesel Generator

Emergency Diesel Generator

Diesel Generator Exhaust has always been a problem.  In the past the nuisance was mostly the smell.  When a hospital would fire up the emergency diesel for the monthly inspection people would complain as diesel exhaust was re-entrained through outside air intakes.  

Now it’s more of an issue.  Diesel engine exhaust is now classified as carcinogenic to humans (Group1). The reclassification was announced on June 12 earlier this year by the International Agency for Research on cancer (IARC). Previously (1988), IRAC had classified diesel exhaust as probably carcinogenic to humans (Group 2A).   For more information on IARC’s evaluation of diesel and gasoline engine exhausts, visit the IARC website.

Strobic Air - Diesel Exhaust Fan

Strobic Air - Diesel Exhaust Fan

High Plume Dilution Fans work well to rid a building of Diesel Generator Exhaust.  A special High Temperature Tri-Stack fan is manufactured by Strobic Air. These fans are available in rigid steel construction designed specifically for high temperature applications (such as emergency diesel generator, furnace or boiler room exhaust). Tri-Stack high temperature exhaust fans are UL certified for operation at 750°F for up to 2 hours without the need for outside air dilution, and incorporate chemical resistant high temperature coatings.

See a prior post for more detail on High Plume Dilution fans for Diesel Generator Exhaust Applications: High Plume Dilution Fans for Diesel Generator Exhaust

More questions on Diesel Generator Exhaust:  askRick?

Ask Rick: Wrap Around Heat Pipes | What is a typical payback?

Posted by Jim Shiminski

Q.  What do you see as typical paybacks for Wrap Around Heat Pipes?  How much does it change with geographical location?

Wrap Around Heat Pipe from Heat Pipe Technology

Wrap Around Heat Pipe from Heat Pipe Technology

Paybacks that we are seeing with typical Wrap Around Heat Pipe applications are ranging from 2 to 4 years.  Paybacks are most influenced by:

  • percentage of cooling coil use –  more use equals more savings
  • system size – paybacks are typically better on larger systems
  • energy cost –  a very big factor in payback for any type of system

 

Wrap Around Heat Pipe: Payback by Location

As expected, the geographical location has a major influence on the payback.  Since the design OA dry bulb is relatively consistent, and the heat pipe is a sensible heat transfer device that reacts only to dry bulb temperature, the same heat pipe selection is actually used for all locations.  The southerly locations do have more hours when cooling is required and the heat pipes can become operative.  Note that the payback is surprisingly low at 26 and 28 months even as far north as St. Louis and Boston respectively, decreasing to 12 months in Puerto Rico.  Bear in mind that coil use drives this chart.  You could also have applications, like laboratories, where cooling is used more often and the wrap around heat pipes would have a quicker payback.   Payback is always application specific.

Please feel free to contact us for a payback on your specific application.

Related Documents from Heat Pipe Technology:  Optimizing Wrap Around Heat Pipes

Related Blog Posts:
Wrap Around Heat Pipe | How does a Wrap Around Heat Pipe work?
Ask Rick: Control for Wrap Around Heat Pipes

 

Air Handling Unit Design | A More Efficient Direct Drive Plenum Fan

Posted by Jim Shiminski

We are using significantly more and more direct drive fans these days.  Annexair,  a leader Energy-Efficient Air Handling Systems, standardizes on direct drive fans for all their units.  They are more efficient, quieter, require less maintenance and last longer (see – 4Reasons Why we choose Direct Drive Fans).  The efficiencies of these fans were a major question in the past which made them less attractive.  That’s changed.

Look at the Direct Drive Plenum Fans manufactured by Ziehl Abegg; a German company that manufactures direct drive plenum fans with the highest efficiency and lowest sound levels in the industry. 

Energy savings with their fan is typically 5 – 15 % higher because of the large back plate and formed, special fan blade inlet (see below).  The large back plate is a simple, yet patented feature that acts to reduce the discharge velocity of air off the blades.  The technology is similar to “Winglets” that we now see on aircraft. 

In terms of a Ziehl-Abegg plenum fan, the lower velocity air stream leaving the impeller serves to reduce turbulence inside the AHU. This in turn reduces both velocity pressure (wasted energy) and noise.  Pressurizing the plenum equally with low velocity air gives designers the flexibility to discharge in any direction they choose. You can’t do that with a scroll fan with the same simplicity as a plenum fan.

Equally important is the benefit of a compact, direct drive motor and impeller combination.  A good solution such as this gets around the huge efficiency losses and ongoing maintenance costs of a belt drive system.  There are additional Energy Savings of 5% because there are no belts involved.

Note that the fan blade does not extend to the edge of the back plate.

Materials for this post were provided by Michael Fulton from Western Mechanical Solutions. 


Related Blog Posts:
Custom Air Handling Units | 4 Reasons to use Direct Drive Fans

 

For more information on Direct Drive Fans;  askRick?

Custom Air Handling Units | Preliminary Design Questions That Are Asked

Posted by Jim Shiminski

Every Custom Air Handling Unit starts with a list of design parameters that must be answered.  If these items are explored and discussed early on it makes for a significantly better design.  Here are the key items that we look for in preliminary Custom Air Handling Unit design.

Lowell General - Air Enterprises Unit AssemblyProject Scope:

  1. Description of application – what will the unit be used for?
  2. What is the budget reality;  Energy efficient unit or low first cost?
  3. Project timeline –  is this a fast track job?

Physical Data:

  1. Indoor or outdoor unit?
  2. Factory or Field built?
  3. Are there design constraints?
    1. Dimensions
    2. Weights
    3. Access
    4. Rigging
  4. Construction Materials
    1. All Aluminum Construction?  Stainless Steel Interior Sections?
    2. Architectural Considerations – Special Coatings?

Lawrence Hospital - All Aluminum Air Enterprises UnitOperational Data:

  1. Unit Type:
    1. Constant Volume (CV) or Variable Air Volume (VAV)?
    2. Standard Unit or Energy Recovery?
    3. 100% Outside Air (OA) or Mixed Air
    4. Draw through or Blow through
  2. Components
    1. Cooling Type (Chilled Water, DX or Heat Pump)
    2. Heating Type (Hot Water, Steam, Gas or Heat Pump)
    3. Filters;  pre & final filters, HEPAs, carbon filters?
    4. Humidification – steam, adiabatic?
    5. UVC lighting?
    6. Lighting package?
    7. Controls package?
    8. Testing?
  3. CambridgeportDesign Parameters
    1. Design Volumes
      1. Supply CFM
      2. Return CFM
      3. Minimum Outside Air (OA) CFM
      4. Exhaust CFM
    2. External Static Pressures
      1. Supply
      2. Return
    3. Design Temperatures and Conditions – both summer and winter
      1. Outside Air (OA) db/wb
      2. Return Air (RA) db/wb (space condition)
      3. Supply Air (SA) db/wb

 This is a start. These are base questions that begin the process.  There are 100’s of options on Custom AHU’s.   If more information is provided in early stages of design,  the process moves quicker and unit design is significantly enhanced. 

Related Blog Posts: 
Custom Air Handling Units | 5 Reasons to use Custom Air Handling Units
Field Erected Air Handling Units | 4 Good Reasons to Assemble an Air Handling Unit On-Site
Custom Air Handling Units | 5 Reasons to use All Aluminum Construction


Ask Rick: High Pressure Humidification | Direction of Nozzles?

Posted by Jim Shiminski

Q. Can you confirm if the dispersion on high pressure manifolds should be into the airstream (against flow) or with the airstream? I have a question from a contractor on this and I wanted to double check with you.

High Pressure Humidification Spray

High Pressure Humidification Spray

In the Carel humiFog system the nozzles point in the direction of airflow so they discharge downstream. Mee Fog is the same now,   although they changed to this in the last two years.  Before then they pointed  nozzles against flow.   This could vary with manufacturers so it is worthwhile to check. 

 

Related Blog Posts:
Ask Rick: How does a high pressure atomizing humidifier work?
Ask Rick: What is adiabatic humidification?

Ask Rick: UVC Emitters | How will UVC provide cost savings?

Posted by Jim Shiminski

Q.  We are considering mounting UVC lights in one of our air handling units.  How much energy do these type of bulbs use?  Is it cost effective to use them?

UVC Emitters

Steril-Aire UVC Emitters

Yes it is.  In commercial, industrial or institutional buildings, a UVC installation offers a quick payback.   Our customers that use UVC lights swear by them.  A typical installation can pay for itself in less than two years and save thousands of dollars thereafter.  This is possible because the devices continually clean coils, drain pans, plenums and ducts.  Energy savings and coil cleaning maintenance savings are the biggest cost benefits with UVC.  A typical bulb uses energy equivalent to a 75 watt light bulb.  Pennies a day in cost compared to dollars of savings.

Key Benefits of Using UVC lights on coils:

  • Energy Savings: Lowers energy costs by improving HVAC system heat transfer and increasing net cooling capacity.

  • Maintenance Savings: Continuously cleans coils, drain pans plenums and ducts, reducing or eliminating manual cleaning and the use of harmful chemicals.

  • Improved IAQ

  • Water Conservation: Reclaiming clean condensate for tower makeup, irrigation or gray water flushing reduces water and waste water costs.

  • Extended food shelf life: Reduces food spoilage

  • Rapid Return on Investment: Offers a return on investment in less than 2 years.

  • LEED Contribution: UVC may contribute to LEED points in one or more areas.

UVC Emitters are manufactured the US by Steril-Aire.

Related Blog Posts:
Ask Rick: What is UVC?
Does Coil Cleaning Save Energy?